Precursors, particularly silicon-containing compounds, and compositions thereof that can be used for the deposition of silicon-containing films, including but not limited to, silicon amorphous silicon, crystalline silicon, silicon nitride, silicon oxide, carbon doped silicon oxide, silicon carbo-nitride, and silicon oxynitride films are described herein. In yet another aspect, described herein is the use of the aza-polysilane precursors for depositing silicon-containing films in the fabrication of integrated circuit devices. In these or other aspects, the aza-polysilane precursors may be used for a variety of deposition processes, including but not limited to, atomic layer deposition (“ALD”), chemical vapor deposition (“CVD”), plasma enhanced chemical vapor deposition (“PECVD”), low pressure chemical vapor deposition (“LPCVD”), and atmospheric pressure chemical vapor deposition.
Several classes of silicon-containing compounds can be used as precursors for silicon-containing films such as, but not limited to, silicon oxide, carbon doped silicon oxide or silicon nitride films. Examples of these compounds suitable for use as precursors include silanes, disilanes, chlorosilanes, polysilazanes, aminosilanes, and azidosilanes. Inert carrier gas or diluents such as, but not limited, helium, hydrogen, nitrogen, etc., are also used to deliver the precursors to the reaction chamber.
Low pressure chemical vapor deposition (LPCVD) processes are one of the more widely accepted methods used by semiconductor industry for the deposition of silicon-containing films. Low pressure chemical vapor deposition (LPCVD) using ammonia may require deposition temperatures of greater than 750° C. to obtain reasonable growth rates and uniformities. Higher deposition temperatures are typically employed to provide improved film properties. One of the more common industry methods to grow silicon nitride or other silicon-containing films is through low pressure chemical vapor deposition in a hot wall reactor at temperatures >750° C. using the precursors silane, dichlorosilane, and/or ammonia. However, there are several drawbacks using this method. For example, certain precursors, such as silane are pyrophoric. This may present problems in handling and usage. Also, films deposited from silane and dichlorosilane may contain certain impurities. For example, films deposited using dichlorosilane may contain certain impurities, such as chlorine and ammonium chloride, which are formed as byproducts during the deposition process. Films deposited using silane may contain hydrogen.
Precursors that are used in depositing silicon nitride films such as BTBAS and chlorosilanes generally deposit the films at temperatures greater than 550° C. The trend of miniaturization of semiconductor devices and low thermal budget requires lower process temperature and higher deposition rate. The temperature, at which the silicon films are deposited, should decrease in order to prevent ion diffusion in the lattice, particularly for those substrates comprising metallization layers and on many Group III-V and II-VI devices. Accordingly, there is a need in the art to provide precursors for the deposition of silicon-containing films, such as silicon oxide, carbon doped silicon oxide, silicon oxynitride, or silicon nitride films that are sufficiently chemically reactive to allow deposition via CVD, ALD or other processes at temperatures of 550° C. or below or even at room temperature.
The reference entitled “Disilanyl-amines—Compounds Comprising the Structure Unit Si—Si—N, as Single-Source Precursors for Plasma-Enhanced Chemical Vapor Deposition (PE-CVD) of Silicon Nitride”, Schuh et al., Zeitschrift Für Anorganische and Allgemeine Chemie, 619 (1993), pp. 1347-52 describes potential single-source precursors for PECVD of silicon nitride films wherein the precursors have the structural unit Si—Si—N such as (Et2N)2HSi—SiH3, (Et2N)2HSi—SiH(Net2)2, [(i-Pr)2N]H2Si—SiH3 and [(i-Pr)2N]H2Si—SiH2[N(i-Pr)2]. The precursor 1,2-bis(di-iso-propylamino)disilane (BIPADS) was used for the PECVD deposition of silicon nitride films. The resulting films from the BIPADS precursor exhibited refractive indices ranging from 1.631-1.814 and had low carbon and very low oxygen contents but high (Si-bound) hydrogen contents.
The reference entitled “1,2-Disilanediyl Bis(triflate), F3CSO3—SiH2—SiH2—O3SCF3, as the Key Intermediate for a Facile Preparation of Open-Chain and Cyclic 1,1- and 1,2-Diaminodisilanes”, Sölder et al., Inorganic Chemistry, 36 (1997), pp. 1758-63 describes high yield syntheses for several open-chain and cyclic diaminodisilanes with fully hydrogenated Si linkages.
The reference titled “Proton magnetic resonance spectra and base strengths of disilanylamines.” Abedini et al., Quarterly Bulletin of the Faculty of Science, Tehran University 3(4): 1-6 discloses PMR spectra of disilanylamines suggested that their basicities decreased in the order: Me3N>H3SiSiH2NMe2>(H3SiSiH2)2NMe>(H3SiSiH2)3N.
U.S. Pat. No. 5,660,895 describes the deposition of high-quality SiO2 films at low temperatures in a PECVD process using disilane (Si2H6) and nitrous oxide.
U.S. Pat. Nos. 7,019,159 and 7,064,083 describe a composition and method of preparing silane compounds or hexakis(monohydrocarbylamino)disilanes that are free of chlorine and have the formula: ((R)HN)3—Si—Si—(NH(R))3 wherein R independently represents a C1 to C4 hydrocarbyl. The hexakis(monohydrocarbylamino)disilane precursors are used for the deposition of silicon nitride or silicon oxynitride films.
U.S. Pat. No. 8,153,832 describes pentakis(dimethylamino)disilane compounds having the formula: Si2(NMe2)5Y where Y is selected from the group consisting of H, Cl, or an amino group and its use for manufacturing gate silicon-containing films or etch-stop silicon-containing films of SiN or SiON.
US Publ. No. 2009/0209081 A describes methods for depositing silicon dioxide containing thin films on a substrate using hexakis(monoalkylamino)disilane such as hexakis(ethylamino)disilane as silicon source and ozone as oxidant. The growth rate was about 1.1 Å/cycle.
U.S. Pat. No. 7,077,904 describes methods for depositing silicon dioxide containing thin films on a substrate using hexachlorodisilane as silicon source and water as oxidant in presence of catalyst such as pyridine. The growth rates were in the range from 2.6 to 0.6 Å/cycle at substrate temperatures from 50 to 140° C.
US Publ. No. 2013/0109155 describes a method of forming a seed layer for a thin film using an aminosilane based gas having two Si atoms such as hexakisethylaminodisilane (C12H36N6Si2). Other aminosilanes having the following formulas may also be used: (1) (R1R2)N)nSi2H6-n-m(R3)m . . . n: the number of amino groups, m: the number of alkyl groups or (2) (R1)NH)nSi2H6-n-m(R3)m . . . n: the number of amino groups, m: the number of alkyl groups. In formulas (1) and (2), R1, R2, R3=CH3, C2H5, C3H7, R1=R2=R3 or may not be the same as each other, n=an integer ranging from 1 to 6 and m=0, and 1 to 5.
U.S. Pat. Nos. 7,446,217; 7,531,679; 7,713,346; 7,786,320; 7,887,883; and 7,910,765 describe silane precursors that comprise at least one disilane derivative that is fully substituted with alkylamino and/or dialkylamino functional groups.